The objective of this project is to study the nature of the modifications of nucleic acid by activated derivatives of the hepatocarcinogen N-hydroxy-2-fluorenylacetamide. The liver enzyme which generates activated fluorenylamine groups capable of reaction with nucleic acid will be studied for the purpose of better understanding its mechanism of action, intracellular location and role in the alteration of nucleic acids in vivo by carcinogenic hydroxamic acids. The possibility that activated fluorenylamine groups may react with bases other than guanine, and the structure of the guanine derivative which results from the instability of fluorenylamine substituted guanine residues will be examined so that methods for the qualitative and quantitative analysis of the alterations of nucleic acids by carcinogenic aromatic amines may be developed. Particular attention will be directed towards the question of whether bases of nucleic acids are modified in vivo by reaction with carcinogenic aromatic amines followed by loss of the aromatic nucleus to yield an altered base. Attempts will be made to determine the fate of the modified nucleic acid groups in vivo. The physical and biochemical effects of the introduction of the fluorenylamine group into nucleic acid will be studied to learn more of the consequences of these reactions.